Hi, I would appreciate ideas for a monster that would need to fit very specific requirements. Basically, the opposite of a glass cannon. A glass cannon hits hard but dies fast. I would like a monster that hits weakly but takes a lot of damage to die. Essentially:

* Attack bonus as low as possible
* Damage as low as possible
* Armor Class as low as possible, to be easily hit
* Hit points as high as possible, to take a lot of damage and require a lot of hits to kill
* CR as low as possible

Bonus points if the monster is something mundanes would recognize.

Bonus points if the monster is D&D 3.5.

Layering templates or conditions on the monster is acceptable, if not optimal. :)

I would appreciate any ideas that would spring to your mind. Thanks for your time in advance.

It seems to me you are describing a wall^^ What you want reminds me of the bonus stages in Street Fighter II where one had to destroy a wall, a car or a pile of barrels as quickly as possible.

More to the point, I'd look at constructs, an animated metallic monster with rusty hinges or something of the kind. I'd even look for something with damage reduction to work in synergy with the large about of hit points.

On You Tube, Puffin Forest described an encounter with a Nalfeshnee Demon (Type IV Demon to you Advanced Dungeons and Dragons players!) that sounds like exactly what you are looking for. In that encounter, it turned out that the party was pretty much unable to get through the Demon's DR, the Demon's Attacks weren't particularly effective against the party.

A brief look at the stat block supports this idea to my eye.

In a PFS adventure, I ran into a Titan Centipede. That seems to fit your bill.

Other than that, I guess like a really big sauropod Dinosaur or some other Animal.